2012-08-12

Teardown: solar powered garden light

Cheap (less than $1) solar powered garden lamp. As many other similar products calling it a light source is questionable - single LED inside has 17 mW, it has small light angle and it's pointed downwards, so significant amount of light is wasted. It may not like heavy rain also as it offers IP43 protection only. I was aware of it, but I bought it for its solar battery only.

Unusual 2/3 AAA 1.2V, 200 mAh NiMH cell. May be able to power LED all the night.
Specialized integrated circuit that works as a boost driver for LED that is active only when no light hits solar battery (in complete darkness).

 Solar battery parameters: open circuit voltage 2.8V, short circuit current 10 mA (close to 60 W light bulb). It's worth noting that it is made of glass - some other lamps I've seen are using cells with plastic top that tend to become mat and stopping sunlight with time (year or two outdoors).

3 comments:

  1. Thought these solar cells were nearer 2v @ 40mA s/c.

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    1. Quite possibly short circuit current may be higher in direct sunlight, open circuit voltage should be accurate though.

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